A typical alternating-current surface discharge type panel used as a plasma display panel (hereinafter referred to as “panel”) has many discharge cells between a front plate and a back plate that are faced to each other. The front plate has a plurality of display electrode pairs each of which is formed of a pair of scan electrode and sustain electrode. The back plate has a plurality of parallel data electrodes. In the panel having this structure, ultraviolet rays are emitted by gas discharge in the discharge cells. The ultraviolet rays excite respective phosphor layers of red, green, and blue to emit light, and thus provide color display.
A subfield method is generally used as a method of driving the panel. In this method, one field period is divided into a plurality of subfields, and the subfields at which light is emitted are combined, thereby performing gradation display. Each subfield has an initializing period, an address period, and a sustain period. In the initializing period, initializing discharge occurs, and a wall charge required for a subsequent address operation is formed. In the address period, address discharge is selectively caused in a discharge cell where display is to be performed, thereby forming a wall charge. In the sustain period, a sustain pulse is alternately applied to the display electrode pairs formed of the scan electrodes and the sustain electrodes, sustain discharge is caused, and a phosphor layer of the corresponding discharge cell is light-emitted, thereby displaying an image.
Of the subfield method, a new driving method is disclosed where light emission that is not related to gradation display is minimized and the contrast ratio is improved (patent document 1, for example). In this driving method, the initializing discharge is performed using a gradually varying voltage waveform, and the initializing discharge is selectively applied to the discharge cell having performed sustain discharge.
The screen size and definition of the panel have been recently increased, and the discharge cells have been further fined. As the discharge cells are fined, it becomes difficult to control the wall charge of the discharge cells, and an operation failure, such as a failure that address discharge does not occur in the discharge cell where an address operation is to be performed, occurs, and the image display quality can be reduced.
[Patent document 1] Japanese Patent Unexamined Publication No. 2000-242224